MOLLUSC A FROM INDIANA AND OHIO 443 



THE INDIANA DEPOSIT 



The material from Indiana is from Flat Rock River, German 

 Township, Bartholomew County. The deposit was discovered 

 and has been studied quite extensively by Rev. W. H. Fluck, of 

 Hope, Indiana, to whom I am indebted for the opportunity of 

 working up this very interesting lot of moUusks. 



Mr. Fluck writes as follows of the deposit and the territory 

 immediately surrounding this place: 



On the surface, everywhere, we have glacial deposits in the form of clay, 

 sand, gravel, and loam. The Illinoian moraine and the ShelbyviUe moraine 

 are both south of these shell deposits. To the north are other moraines. In 

 fact, the Flat Rock River flows a part of its course between moraines, to the 

 north and east of the "Bartholomew Deposits," as I call the shell place. The 

 top stratum, a sandy loam, in which the shells are found, is from two to twelve 

 or more feet deep. Below this there is good gravel and sand. The river banks 

 are twelve to fifteen feet high. On the east side of the river there is an open 

 gravel bed where I also took shells. The shells range from just beneath the 

 soil to as far down as I could examine, that is, down to the river surface, ahd, 

 I suspect, down to the Devonian rock, over which the glacial deposits now lie. 

 To be clear, on the east and west side of the river, and all along for several 

 miles, below the Wisconsin drift, the sheUs are found. I have not explored 

 north of this. On the west side, the shells come from a steep bank in which 

 the shells are imbedded at all depths. On the east side, at about twenty-five 

 yards back from the bank, I took some from an open gravel bed, not out of the 

 gravel, but from the sandy loam above the gravel. The sample of soil and 

 sheUs I am sending you came from the west bank, at about twelve feet below 

 the surface. 



The shells in the deposit seem referable to the Sangamon inter- 

 glacial interval. The deposits of sand, sandy loam, and gravel are 

 in valleys that were used as Hnes of drainage from the early and 

 late Wisconsin ice sheets (see Leverett, 1902, PI. II). The Illinoian 

 till is only four or five miles west of Flat Rock River and the 

 material in the stream valleys appears to be outwash or drainage 

 material from the later ice sheets. Of the Sangamon interval in 

 Indiana, Leverett says: 



The Sangamon soil and weathered zone may be seen beneath the surface 

 silt in thousands of exposures in southeastern Indiana and southwestern Ohio, 

 for the general thickness of the soil is only four or five feet. Farther north 



